FAR better than the stock barrel. I got one when they first came out for my 9.1 and have used them on 8.1. You will be able to notice the difference immediately! Better accuracy hands down than the stock barrel. I use regular paint and FS with this barrel.

Quick question(s): What size are the fs rounds? I've heard .687 but I also heard a .690 will work just as well. I saw that you can get the str8 shot in either .686 or .690. Would underborring be a good idea for this rounds? I'd imagine if its rubbing against the barrel it would slow it down thus reducing range(accuracy too??). But then again if its overbored then it would bounce around inside the barrel thus reducing both range and accuracy(Right?). I'm getting a t9.1 ranger soon and the only thing i'mma use it for is "sniping" so any and all info you guys can give me in this regard will be greatly appreciated.

Basically with barrels and paint rounds you want a boundry layer of air all around the ball, nothing too big. But nothing to small that it will rub on the barrel. FS rounds typically are .685" to .687" (most of mine are .685 after measuring them all)

underboaring the barrel will cause a loss of accuracy and range as the ball will be "forced" through the barrel.

Overboaring will cause an extreme loss in accuracy as the round will "tumble" through the barrel and the trajectory as it leaves the barrel is totally unknowable.

Personally id say keep around .685. To me thats the best performance size

Personally id say keep around .685. To me thats the best performance size

Good stuff! That pretty much answered my question Now I got one more. Does anyone have any experience with the .686 variation? I've heard the .690 has really good consistency but haven't seen to much about the .686 and I've been googling like crazy about this.

I might be years late into this conversation, but I have a .686 Lapco Barrel. It seems to work very well and accurate on targets. I only one ball break in the marker (T8.1), I would love to know that are the Lapco barrels more accurate then the Hammerhead barrels? Since the Hammerhead's are so rare to find (as I know they are much quieter).